Water-management startup PureSense has closed $4.5 million in its first round of funding, CEO Craig Buxton said Thursday.

Venture-capital firm One Earth Capital led the round.

Emeryville, Calif.-based PureSense plans to use the money to grow sales of its water-saving systems, which monitor soil changes to help farmers use less water for irrigation.

Using probes, sensors, weather instruments and meters, PureSense calculates the moisture and nutrients in the soil. It uses the Internet to send the information to servers, then uses software to analyze whether or not the crops are getting the right amount of water.

Farmers can get results on the Web, cell phones or other devices, and the system also alerts farmers of potentially crop-damaging weather.

The knowledge helps customers save water -- particularly important considering agriculture uses approximately 70 percent of the world’s fresh water -- and reduce their operating expenses by 20 percent, Buxton said.

PureSense isn’t the only company looking to reduce water usage.

Among others, Petaluma, Calif.-based HydroPoint Data Systems sells a water-management system that uses satellite data and weather-predicting software to reduce the amount of water used for irrigation.

In September, the company added a "material investment" to its $19 million Series-B round (see IN BRIEF: HydroPoint Gets Cash).

PureSense, which was pitching investors at the Cleantech Forum this week in the hope of raising $8 million to $10 million in a second round, was one of several startups seeking investors at San Francisco event (see this VentureBeat post).

Among others were Hycrete and Simbol Mining.

Hycrete, which makes concrete that the company claims is recyclable, waterproof and less toxic than regular concrete, is looking for a lead investor to help close on a third round of funding.

CEO David Rosenberg told Greentech Media that Hycrete wants to raise between $10 million and $20 million. He also expects previous investors RockPort Capital Partners and NGEN Partners to participate in the round.

The company will use part of the money to grow in the United States and internationally.

Hycrete is already making moves abroad. On Thursday, Greentech Media reported that Hycrete would provide concrete for what will be the tallest building in Mumbai (see Next Cleantech Hub: India?).

Simbol Mining, which claims it has developed a process to produce lithium from geothermal brine, a waste byproduct of geothermal-energy production, also is chasing a $5 million round.

While a number of technologies, such as electric vehicles, hope to use lithium-based batteries to boost their range, the Houston-based startup said there isn’t enough "economically recoverable" lithium on the Earth’s crust to meet the expected demand.

Simbol believes it can recover $6.6 billion worth of lithium, as well as $16.6 billion from other materials, from brine that currently is thrown away.

Luka Erceg, president of Simbol Mining, said the company is nearing completion of its first pilot facility to demonstrate its technology.

The Cleantech Group also named Simbol Mining winner of the "Most Promising Technology" award Thursday.